Device for molding hollow display forms



Aug. 12, 1952 B. P. COOPER DEVICE FOR MOLDING HOLLOW DISPLAY FORMS 5 Sheets- Sheet 1 Filed April 1, 1950 jiwentor Basil P Cooper By his Attorney Aug. 12, 1952 B. PL COOPER 2,606,343

DEVICE FOR MOLDING HOLLOW DISPLAY FORMS Filed April 1, 1950 5 Sheets-Sheet 2 "ZILF [nveniar Basil P Cooper By his Attorney B. P. COOPER DEVICE FOR MOLDING HOLLOW DISPLAY FORMS Aug. 12, 1952 5 Sheets-Sheet 3 Filed April 1. 1950 12, 1952 B. P. COOPER DEVICE FOR MOLDING. HOLLOW DISPLAY FORMS 5 Sheets-Sheet 4 Filed April 1, 1950 Inventar Basil P Cooper By his Attorney g- 12, 1952 v I B. P. COOPER 2,606,343

DEVICE FOR MOLDING HOLLOW DISPLAY FORMS Filed April 1, 1950 70 W T 68 42 g i I J 30 14 -fi Z2 Z6 a. v 3a Elly 7 46 J4 40 60 7 6 V 50 "1 'i f IIIE/ A J LIU 59 45 li'zventor Basil 1? Cooper 5 Sheets-Sheet 5 Bi his Attorney Patented Aug. 12, 1952 DEVICE FOR MOLDING HOLLOW DISPLAY FORMS Basil Pomeroy Cooper, Leicester, England, as-

signor to United Flemington, N. 11., a

Shoe Machinery Corporation,

corporation of New Jersey Application April 1, 1950, Serial No; 153,357 H In Great Britain April12, 1949 r 7 Claims. (01. 18-19) This invention relates to machines for theproduction ofLhollow moldedarticles and is herein described as applied to the automatic production of hollow hosiery-display forms of plastic material. With the aid of such machines, there may be carried out substantially the method described in Letters Patent of the United States 'No. 2,029,706, granted February 4, 1936, upon theapw plication of William J. De Witt.

In the method described the patent the forms are produced by expanding a hollow tube of previously softened plastic material within a mold by which the shape of the article is determined. The prior apparatus for carrying out the patented method utilizes a two-part mold arranged to grip and close one end of the tubular material. At the other end, a suitable plug is provided so thatsteam or hot water may be introduced to expand the material to fit the mold. Commonly at that time the mold is immersed in a bath of hot water. After a suitable interval, the water is expelled from the interior of the form by means of compressed air, the pressure of which is maintained while the form is set and the. mold cooled by the application thereto of cold water, sometimes inthe form of a spray. The molded tube may then be removed from the mold and finished by trimming or other similar treatments to produce a form a commercially dee sirable characteristics. Carrying this process but manually involves a substantial amount of skill and effort on the partiof the operator in handling the mold and operating necessary valves at desired intervals. f The objectof this invention is to provide an improved machine in which the operator is only required to load and unload the molds, the other steps being carried out automatically.

In one embodiment, the machine is provided with a movable carrier herein illustrated as rotatable, in which there is a conduit leading to each mold and an automatic valve mechanism for connecting these conduits successively to a source of heated fluid under pressure and later to a source of air under pressure so that the form is expanded to fit the mold by the heated fluid and is set and held, during the cooling period, by means of the compressed air. This valve mechanism may conveniently be arranged to be operated by the movement of the carrier and it is illustrated as having one portion which is part of the carrier so that the rotation thereof inherently operates the valve mechanism.

; in. order to expedite the cooling of the molds andjthe settingiof the'forms, the machine is pro- 2 q v a vided with a device for spraying cooling water over each successive mold and, in accordance with a feature of the invention, the machine is provided with valves operated by the rotation of the carrier for automaticallyturning :on 'and shutting off the supply of cooling';water.'" v r Inasmuch as the cooling takes place after'the successive forms have been lifted out of the hot water bath, the point of application of the cooling spray is necessarily above the hot water bath. It willbe recognized, however, that the mixture of the cool water with the hot water bath is un desirable and provision is made, in accordance with another feature of the invention, for catching and carrying off the cooling waterso that it will not reach the hot water. The arrangement shown involves the use of casings around the individual molds which, while they do not interfere with the clipping of the molds in the hot water bath, are effective in the spraying position to catch the sprayed water and to transfer it'to a trough at the center of the rotatable carrier by which it is diverted and drained into a cold water tank.

Another feature of the invention which con tributes to the easy automatic operation of the machine resides in a specially constructed plug associated with the inlet conduit by which either hot water or compressed air is led to the interior time form.' It will be recognized that the forms being expanded by" the hot water are located within the tank of hat water at the time when compressed air is supplied to blow out thewater and' to' start the setting of the form. Accordingly, this novel'plug includes a relief valve com municating with a sleeve; surrounding the inlet conduit,'through which the'hot water may be exhausted intoflthe tank when driven out by the compressed air. The'sleeve'has the added'function of controlling the setting of the relief valve, it being so positioned as to abut one end'of the springiwhich closes that valve. f i I These and other features of the invention will best be understood from a consideration of the following specification taken in connection with the accompanying drawings in which T Fig. 1 is a front elevation of the machine; F Figl. 2 is a side elevation taken from the left of 1g. I Fig, 3 is another side elevation taken from the right of Fig.1 r

Fig. 4 is a fragmentary elevation, partly in section on the line IVIV in Fig. 5, showing the main control valve;

.Fig.;5 .is a fragmentary enlarged front eleva- 3 tion of the left end of the rotatable carrier of Fig. 1, showing in axial vertical section the valve mechanism also shown in Fig. 4

Fig. 6 shows in front elevation, on a reduced scale, that one of the molds which is at the loading station and the manner of mounting it upon the carrier;

Fig. 7 is an axial section on a larger scale through the inlet end of one of the molds; and

Fig. 8 is a transverse section therethrough on the line VIII-VIII of Fig. 7.

The machine as a whole comprises a rotatable carrier III for a series of molds I2 and this carrier or turret is mounted for rotation upon .a fixed shaft I4 extending between two end frames I6 and I8. Disposed between these end frames is a tank 20 for a hot water bath containing water at a temperature which may, for example, be 180 F. The rotatable carrier I is made up of end spiders 22 and 24 each having four arms which are joined by cross bars 26. On each cross bar there is bolted a two-part mold casing 38 (Fig.6) having the two parts hinged together, as illustrated in the De Witt patent mentioned above. In this moldv there is disposed a tubular work piece which will ultimately be expanded as shown in 'Fig. '7 to make a hosiery display form 40. The two parts of the mold are'held together during the making of the form by a series of clamps 42.

In one end of the form, provision is made for the introduction of steam or compressed air through a tubular inlet conduit 44 centralized within a mold closing plug 46 by means of an end plate 48 attached thereto by means of screws. This end plate is provided with a series of apertures 50 around the conduit 44 which are normally closed by a relief valve 52 held in contact therewith by a helical spring 54 the outer endof which abuts the end of a sleeve 56. This sleeve is threaded in the plug 46 and'may be adjusted to control the tensionof the spring after which it is locked in adjusted position by a locknut 58. The left end of the sleeve is open to permit the hot water to be blown out through a passage 59 back into the tank when compressed air is supplied through the tubular member 44. Surrounding each ofthe' molds and also mounted upon the crossbars 26 of .the carrier rare individual hollow casings 60 which are open at their outer circumferences and are contractedlto a delivery slot 62 at their inner circumferences .(Fig. 4)..

At the left in Fig. '3 and hence at-thefront .of the machine is a loading station L where pieces of tubular material are introduced'in the molds. It will be understoodthat, in the continued operation of the machine, any mold which is moved upto the loading station contains a finished form which must first .be'removed by the operator by releasing the clamps '42 and removing a plug 46 from the neck 64 (Fig. '7") of each form, after slipping off a gripping ring 65. This operation is facilitated by using a piece of flexible tubing 66 (Fig. 6) which is joinedby a union to the outer end of each tubular member 44.

These pieces of tubing'are connected by another union "I0 to conduits such as that at I2 shown in Fig-6 as supported in an end wall of the associated casing 60. v

Any desired mechanism, either power driven or manually operated, may be employed for rotating the carrier'through steps of 90 to-carry out the method! Shown in the' drawings herein is a manually operated shaft 14 (Fig.3) joined by a worm I6 to a-gear 18 which is secured'to the right hand spider 24 of the carrier. The shaft 14 is provided with a handle to enable manual rotation thereof by the operator. This rotation of the mold carrier in the direction of the arrows shown in Figs. 2 and 3 serves to bring each mold to the loading station L at the front of the machine then down into the hot water bath. Subsequently, each mold is raised during the continued rotation of the carrier and is then brought to the top position so that it may be sprayed with cold water from a transverse perforated pipe 82 (Fig. 1) and then carried forwardly and downwardly to the loading station.

In order to make the operation of the machine substantially automatic, a valve V is provided in which the conduit I2 and similar conduits 04, 86 and 68 are brought toward the axis of the carrier and threaded in ports in a sleeve 90 of a valve member which is rotatable with the carrier. This sleeve 90 surrounds the fixed shaft I4 and is secured to a hub 92 on the spider 22 at the left side of the carrier. Packings 94 and 96 are associated with the sleeve 90 and are compressed within the hub 92 by a packing ring I 00 to insure a pressure tight joint between this valve sleeve 90 and theshaft.

Inasmuch as it is desired to fill each mold with hot water at one step in the rotation of the carrier, the fixed shaft I4 is provided with a passage I02 joined by a conduit I04 to a pump I06. motor operated and receiving its supply of hot water through an inlet I08 connected to the tank 20. In this conduit I04 there is a relief valve IIII having an exhaust pipe II2 (Fig. 1) which'empties into the tank 20. Thus, when the pressure in the passage I02 exceeds the setting of the relief valve, the water forced upward by the pump I06 will be carried back into the tank. The fixed shaft is also provided at its left end with another passage II4 adapted to be joined by a vertical conduit I I6 to a supply of compressed air. These passages I 02 and II 4 open into radial ports H8 and I20 terminatingin annular grooves I22 and I24.

During the rotation of the carrier the successive conduits 12,84, 66 and 86 come into register with these annular grooves I22, I24 and, by reason of a'predetermined extent'of said grooves around the periphery-of the fixed shaft, provide a timing arrangement by means of which :there is controlled, first, the "admission of hot water through the passage I02 to thegroove I22 and thence to the associated conduit joined to the mold which is approaching the bottom position.

Subsequently, the conduit of that particular form will be raised upwardly toward theme: of the machine into a position such-as that 'shown by the conduit 86 and there it will receive compressed air'led into it through the passage I14 and the groove I24 through an extended period such that the hotwater is pushed out through the relief valve -52 and the sleeve 56 and the expanded form is held under pressure in expandedcondition until the form reaches its uppermost position where its mold 'is subjected to the cooling spray from the perforated -pipe62.

'Thispipe is joined by-a-conduit I26 to a cold water pump I28 (Fig-3) supplied by means of a cold water tank 110. valve in this conduit I26, opened by depression of a pressbutton I22 (Figs. 1 and 3) in-the valve, is mounted -upon a bracket I34 extending rearwai'dly from the top of the right-handframe .I 8. On each-of the'arms of the right-handspider 24 are securedcams I36 which depress the :button I32 in the valve in the c'old'water supply-conduit I26 and cool the uppermost form by a spray delivered'from the pipe 82 at the top.

As previously mentioned, the cooling point is directly above the hot water tank 20 and it is not desired that the cold Water from the spray 82 shall be mixed with the hot water. Accordingly, the fixed shaft I4 is provided with a receiving trough I48 (Figs. 1 and 4) which has one or more outlet pipes 142 terminating within an axial drain passage I44 in the fixed shaft 14 and to the right of the Valve passages previously described. The outer end of this drain passage is connected by a conduit H36 (Figs. 1 and 3) which leads back to the cold water tank I36.

Thus, in the operation of the machine, it is only necessary for the operator to cause rotation of the turret carrier IE! to bring a mold to the loading station L and at that point to remove a finished form and to insert a tubular piece of material. Having then closed the mold and tightened the clamp 42, the process will be carried out automatically of passing the molds through a hot water bath which is allowed to flow around each mold l2 through the open outer circumference of the associated casing 60. Thereupon hot water under pressure will be forced into the interior of the mold to expand the tubular plastic to fit the mold. This expansion having been completed, the valve V will act to introduce compressed air which will force out the water in the mold through the passage 59. At the end of this stage the mold will be cooled by the application of a spray of cold water to set the work, after which the mold will be returned to the loading station L.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine for molding hollow display forms, a fixed shaft, a carrier rotatable upon said shaft having a series of molds mounted thereon, casings around said molds open at their outer sides, a device for spraying water on the molds to cool them at a predetermined point in the cycle of rotation, said shaft having an exhaust passage extending therethrough, and means for receiving water collected by said casings as they individually come to the spraying position and delivering it to the passage in said shaft for disposal.

2. In a machine for molding hollow display forms, a fixed shaft, a carrier movable thereon, a drain passage in said shaft leading to one end thereof, a receiving trough connected to said passage, a series of molds on said carrier, casings open at the bottom surrounding said molds and adapted to be brought into position to empty into said trough, a hot water tank beneath the carrier into which the molds are dipped, a cold Water tank, means for connecting said drain passage to said latter tank, a spraying device, means for operating said spraying device when the individual casings are in cooperative relationship with said trough, and means for ex- 6 panding forms in said molds and holding a form in expanded condition during the period of operation of said spray to set the form.

3. In a machine for molding hollow display forms, a hollow mold adapted to receive a tubular blank of plastic material, a plug adapted to be positioned in such a blank at one end thereof, means for securing said plug and the blank in one end of said mold to fill it, an inlet conduit for pressure fluid supported by said plug, a sleeve threaded in the outer end of said plug around said conduit, said plug having an exhaust passage communicating with the interior of said sleeve, a relief valve controlling said passage, a spring for said relief valve abutting one end of the sleeve, and means for holding said threaded sleeve in position after the compression of the spring has been adjusted by rotation of the sleeve in the plug.

4. In a machine for molding hollow display forms, a hollow mold adapted to receive a tubular blank of plastic material, an annular plug adapted to be positioned in such a blank at one end thereof, means for securing said plug and the blank in one end of said mold to fill said end, an inlet conduit for introducing fluid under pressure to the inside of the blank, an end plate secured to the inner end of said plug, said end plate supporting said inlet conduit, ports in said end plate around said conduit, a valve for closing said ports, a helical spring having one end pressing against said valve, an open ended sleeve threaded in the outer end of said plug and abutting the other end of said helical spring, and means for securing said sleeve in adjusted position.

5. In a machine for molding hollow display forms, a hot water tank, a carrier mounted for rotation above said tank, a series of molds mounted on said carrier for immersion in said tank upon rotation of the carrier, a cooling spray above the carrier, and means operated by rotation of the carrier for controlling said spray.

6. In a machine for molding hollow display forms, a hot water tank, a carrier mounted for rotation above said tank, a series of molds mounted on said carrier for immersion in said tank upon rotation of the carrier, a cooling spray above the carrier, means operated by rotation of the carrier for controlling said spray, and means for receiving and diverting the sprayed material to prevent its addition to the contents of the tank.

'7. In a machine for molding hollow display forms, a hot water bath, a carrier provided with a series of molds positioned to pass the molds through the bath, means for automatically applying fluid-pressure to the form in the mold during the passage of the mold through the bath, a spray nozzle above the carrier, and a carrieroperated valve for controlling said nozzle.

BASIL POMERO-Y COOPER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,277,607 La France Sept. 3, 1918 1,537,697 Roberts May 12, 1925 2,348,738 Hofmann May 16, 1944 2,354,029 Kingston July 18, 1944 

